Turnbull must refer Lib MP to court: Labor

Malcolm Turnbull will need to toughen his solution to the MP citizenship fiasco to get Labor on board.

Mr Turnbull and Opposition Leader Bill Shorten will meet in Melbourne on Wednesday to discuss a way forward, as Liberal MP John Alexander faces pressure to refer himself to the High Court over his potential dual UK citizenship.

Labor says Mr Alexander's case of citizenship by descent through his British-born father is close enough to that of disqualified senator Fiona Nash and resigned senator Stephen Parry that the court should assess it.

However, the prime minister - who announced a plan on Monday for all MPs to declare their citizenship on a public register - said he was not going to "start front-running this process" by second-guessing Mr Alexander's status.

"People should make their declarations and then cases can be referred," Mr Turnbull told ABC radio.

"Obviously, if a member believes that they are a dual-citizen now and are ineligible to sit in the parliament, then they should resign. But ... I take it as a given that every member of the House and the Senate, as of today, believes that they are eligible to sit in the House or the Senate."

Mr Alexander, the MP for Bennelong, is seeking advice on whether he is a UK citizen through his father Gilbert Alexander who was born in England in 1907 and arrived in Australia in 1911.

A search of British records found no trace of Gilbert Alexander, who died in 1987, having formally renounced his UK citizenship before his son was born in 1951.

However, British citizenship expert Philip Gamble told Fairfax Media that under UK law Mr Alexander would be a citizen by descent unless he took formal steps to renounce British nationality.

Labor frontbencher Penny Wong said the prime minister needed to take action.

"John Alexander must be referred to the High Court. Malcolm Turnbull must refer John Alexander to the High Court," Senator Wong said in Adelaide.

Labor would be seeking to ensure the disclosure process proposed by Mr Turnbull was completed by the last day of parliament for the year, December 7.

Mr Turnbull's plan involves giving MPs 21 days from the passing of a resolution, which would not be until November 27 at the earliest.

"To try and ensure Australians don't know the truth about the citizenship of members of parliament or the eligibility of his own MPs until next year, we don't think that's good enough," Senator Wong said.

Mr Alexander says his father became an Australian citizen "as soon as he could".

"I understand he renounced his British citizenship before I was born, because he was a proud Australian," Mr Alexander said in a statement.

If Mr Alexander is disqualified from parliament, the government - which holds a one-seat majority and is already fighting a by-election in New England - would be forced to a by-election in Bennelong, which the MP holds with a 7.8 per cent margin.

Crossbench senator Derryn Hinch said he would support a Greens motion next week to have a parliamentary committee, advised by citizenship experts, conduct an audit of all senators.